One in four teenage girls has received the relatively new vaccine against cervical cancer, as per the federal health officials. The figures represent the government’s first substantial study of vaccination rates for the vaccine, Gardasil, which is Merck & Company’s heavily advertised three-shot series that goes after the sexually transmitted human papillomavirus, or HPV. The vaccine protects against strains of the virus that cause about 70 percent of cervical cancers.

Health officials recommend that girls get the shots when they are 11 or 12, if possible, before they become sexually active. Also, 11 is the age when children are generally due for a round of vaccinations. The survey covered children only from 13 to 17. Proponents of the vaccine had been hoping for much higher vaccination rates, saying the shots could significantly reduce the nearly 4,000 cervical cancer deaths that occur each year in the United States.

Many families were cautious about the safety of new vaccines which are given to their children during the research. Other aspects of the vaccine may also give some families pause.

The Centers for Disease Control and Prevention based the study on household telephone surveys in late 2007. The survey results cover from when the vaccine came on the market, in mid-2006, to when the survey questions were answered.

The results are based on nearly 3,000 girls ages 13 to 17 for whom the researchers could verify vaccination information through medical records.